Question

10.An object is kept at a distance of 15 cm from a
(a) convex mirror
(b) concave lens (c) Plane mirror.
The focal length of the convex mirror and the concave lens are 10 cm each.
Draw the appropriate ray diagrams, showing the formation of image, in each of the three
cases.​

Answer 1

Explanation:

Here point I would be center of curvature of the mirror.

So focal length of mirror f=

2

MI

For lens,

f

1

=

v

1

−

u

1

v

1

=

f

1

+

u

1

Here , f=+10cm,u=−15cm

v

1

=

10

1

+

−15

1

v=+30cm

MI=LI−LM

=30−10=20cm

f=

2

MI

=

2

20

f=10cm